On Wed, 29 Jun 2011 08:31:58 +0100, David Laight wrote:
On Tue, Jun 28, 2011 at 03:18:47PM -0700, Juan Lang wrote:
>> This is a false positive. ?h_addr_list is declared as a char **,
and
>> technically it is, but gethostbyname only returns IPv4 addresses,
i.e.
>> ones that can fit in a DWORD.
>
> That doesn't sound like a problem that would give that warning.
Why not? A cast of a pointer to a DWORD with 64-bit pointers would
cause truncation, if it were indeed a pointer that were being cast.
It isn't, even though it's declared that way.
But 'char **h_addr_list;' is a pointer to an array of pointers
to address buffers (defined as char) - not a pointer to an array of
addresses.
IIRC the 'something' will be an IPv4 address - which might
be held as a 32 bit quantity rather that an array of char.
But nowhere should you cast the 32bit int (DWORD) to/from a pointer
type.
David is right, the address is not stored as a pointer but as a DWORD
in place of the chars. Like this:
gethostbyname("winehq.org"):
wrong: (DWORD) host->h_addr_list[i] = 0x00cbd1c8 = 200.209.203.0
right: *(DWORD*) host->h_addr_list[i] = 0x86192ed1 = 209.46.25.134
--
Lauri
